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1.
This paper describes the design and fabrication of a MEMS guide plate, which was used for a vertical probe card to test a
wafer level packaged die wafer. The size of the fabricated MEMS guide plate was 10.6 × 10.6 cm. The MEMS guide plate consisted
of 8,192 holes to insert pogo pins, and four holes for bolting between the guide plate and the housing. To insert pogo pins
easily, an inclined plane was defined at the back of each hole. Pitch and diameter of the hole were 650 and 260 μm, respectively.
In order to define inserting holes and inclined planes at an exact position, silicon MEMS technology was used such as anisotropic
etching, deep reactive etching and more. Silicon was used as the material of the guide plate to reduce alignment mismatch
between the pogo pins and solder bumps during a high temperature testing. A combined probe card with the fabricated MEMS guide
plate showed good x– y alignment and planarity errors within ±9 and ±10 μm at room temperature, respectively. In addition, x– y alignment and planarity are ±20 and ±16 μm at 125°C, respectively. The proposed MEMS guide plate can be applied to a vertical
probe card for burn-in testing of a wafer level packaged die wafer because the thermal expansion coefficient of the MEMS guide
plate and die wafer is same. 相似文献
2.
Tactile metrology with deep and narrow micro holes was addressed using extremely slender piezoresistive micro cantilever sensors.
Linear strain–displacement characteristics were observed with this sensor operated under transversal and axial loading. From
noise, non-linearity and repeatability measurements the resolution and uncertainty of the cantilever sensors were determined
to few nm and few tens of nm, respectively, within a micron displacement span. Under axial loading buckling of the cantilevers
was observed after exceeding the critical limit of an Euler beam under the boundary conditions of a clamped-pinned beam. The
cantilevers typically survived displacements well above the buckling limit, i.e., fracture of 3-mm long cantilevers was only
observed at displacements of more than 200 μm. The feasibility of the cantilever as an active 1D touch probe for high-aspect-ratio
blind holes was demonstrated at a dry-etched silicon high-aspect-ratio microstructure. As an application example with a high-volume
product we investigated the form and roughness of diesel injector nozzle spray holes. 相似文献
3.
Most heterogeneously catalyzed gas–liquid reactions in micro channels are chemically/kinetically limited because of the high
gas–liquid and liquid–solid mass transfer rates that can be achieved. This motivates the design of systems with a larger surface
area, which can be expected to offer higher reaction rates per unit volume of reactor. This increase in surface area can be
realized by using structured micro channels. In this work, rectangular micro channels containing round pillars of 3 μm in
diameter and 50 μm in height are studied. The flow regimes, gas hold-up, and pressure drop are determined for pillar pitches
of 7, 12, 17, and 27 μm. Flow maps are presented and compared with flow maps of rectangular and round micro channels without
pillars. The Armand correlation predicts the gas hold-up in the pillared micro channel within 3% error. Three models are derived
which give the single-phase and the two-phase pressure drop as a function of the gas and liquid superficial velocities and
the pillar pitches. For a pillar pitch of 27 μm, the Darcy-Brinkman equation predicts the single-phase pressure drop within
2% error. For pillar pitches of 7, 12, and 17 μm, the Blake-Kozeny equation predicts the single-phase pressure drop within
20%. The two-phase pressure drop model predicts the experimental data within 30% error for channels containing pillars with
a pitch of 17 μm, whereas the Lockhart–Martinelli correlation is proven to be non-applicable for the system used in this work.
The open structure and the higher production rate per unit of reactor volume make the pillared micro channel an efficient
system for performing heterogeneously catalyzed gas–liquid reactions. 相似文献
4.
We have incorporated microspheres, from 50 to 80 μm in diameter, of periodic mesoporous organosilica (inner surfaces up to
1,000 m 2/g and pore sizes in the nanometre range) with two types of organic functionalities (benzene and ethane bridges, respectively)
inside microstructured channels (each 200 μm wide and 100 μm deep) and, exemplarily, monitored by Raman microscopy (Raman
spectroscopy through microscope optics) that the temperature characteristics of the adsorption–desorption equilibria of benzene
and ethanol vary significantly with the type of organic functionality of the microspheres and the pore morphology. The integration
of this class of nanostructured material into devices by means of microchannels is a promising novel approach to, among others,
substance separation in analytics, micro process engineering, and micro chemistry. 相似文献
5.
Microtechnology becomes a versatile tool for biological and biomedical applications. Microwells have been established long
but remained non-intelligent up to now. Merging new fabrication techniques and handling concepts with microelectronics enables
to realize intelligent microwells suitable for future improved cancer treatment. The described technology depicts the basis
for the fabrication of electronically enhanced microwell. Thin aluminium sheets are structured by laser micro machining and
laminated successively to obtain registration tolerances of the respective layers of <5 μm. The microwells lasermachined into
the laminate are with 50–350 μm diameter, allowing to contain individual cells within the microwell as well as provide access
holes for the layer-to-layer contacting. A permeable membrane attached to the bottom of the microwell plate is used for fluid
handling. The individual process steps are described and results on the microstructuring as well as on biocompatibility of
the materials are given. 相似文献
6.
A micromachined electro-thermal gripper, first introduced by Ivanova et al . (Microelectron Eng 83:1393–1395, 2006), represents a promising candidate for the manipulation and handling of micro or even
nano-scaled objects. To further optimize the performance of the device, a detailed electrical and mechanical characterization
is needed. Due to the so-called duo-action gripper approach (i.e., a separate actuator for closing and opening action) these
investigations focused on the maximum (minimum) opening width being 11.5 μm (3.3 μm), while in rest position a value of 4 μm
is feasible. The maximum, electrical input power is limited to 80 mW/actuator element, resulting in a current density of up
to 1.27 MA cm −2 in the corresponding metal layers. When applying, however, larger current densities the probability of device failure increases
substantially as in combination with an enhanced temperature of about 200°C electromigration effects occur in the metallization.
Furthermore, the cut-off frequency and parasitic effects during actuation such as the z-deflection and the increase in length
of each arm both showing values of up to 3 μm have been investigated as a function of operation parameters. Finally, the tips
of the gripper were sharpened using Focused Ion Beam technique to a radius of less than 1 μm for gripping operations in space-restricted
environments or for the manipulation or handling of sub-μm scaled objects. 相似文献
7.
This paper presents the design and fabrication of a micro Pirani gauge using VO
x
as the sensitive material for monitoring the pressure inside a hermetical package for micro bolometer focal plane arrays
(FPAs). The designed Pirani gauge working in heat dissipating mode was intentionally fabricated using standard MEMS processing
which is highly compatible with the FPAs fabrication. The functional layer of the micro Pirani gauge is a VO
x
thin film designed as a 100 × 200 μm pixel, suspended 2 μm above the substrate. By modeling of rarefied gas heat conduction
using the Extended Fourier’s law, finite element analysis is used to investigate the sensitivity of the pressure gauge. Also
the thermal interactions between the micro Pirani gauge and bolometer FPAs are verified. From the fabricated prototype, the
measured device TCR is about −0.8% K −1 and the sensitivity about 1.84 × 10 −3 W K −1 mbar −1. 相似文献
8.
In order to develop a new structural microwave probe, we studied the fabrication of an AFM probe on a GaAs wafer. A waveguide
was introduced by evaporating Au film on the top and bottom surfaces of the GaAs AFM probe where a tip 7 μm high with a 2.0
aspect ratio was formed and the dimensions of the cantilever were 250 × 30 × 15 μm. The open structure of the waveguide at
the tip of the probe was obtained by FIB fabrication. An AFM image and profile analysis for a standard sample, obtained by
the fabricated GaAs microwave probe and a commercial Si AFM probe, indicate that the fabricated probe has a similar capability
for measurement of material topography as compared to the commercial probe. 相似文献
9.
Radio frequency micro electro-mechanical systems (RF MEMS) vertical cantilever variable capacitors fabricated using deep X-ray
lithography and electroplating are presented. Polymethylmethacrylate (PMMA) layers of 100 μm and 150 μm have been patterned
and electroplated with 70 μm and 100 μm thick nickel. A 3 μm thick titanium layer was used as plating base as well as etch
time-controlled sacrificial layer for the release of the cantilever beam. The parallel plate layout includes narrow gaps and
cantilever beams with an aspect ratio in nickel of up to 60 for 1 mm long features. Auxiliary structures support the beams
and gaps during the processing. Room temperature electroplating significantly reduces the risk of deformations compared to
the standard process temperature of 52°C. The capacitors operate in the 1–5 GHz range, and demonstrate good RF performance,
with quality factors on the order of 170 at 1 GHz for a 1 pF capacitance. 相似文献
10.
In this paper we present a new roll-to-roll embossing process allowing the replication of micro patterns with feature sizes
down to 0.5 μm. The embossing process can be run in ‘continuous mode’ as well as in ‘discontinuous mode’. Continuous hot embossing
is suitable for the continuous output of micro patterned structures. Discontinuous hot embossing has the advantage that it
is not accompanied by waste produced during the initial hot embossing phase. This is because in ‘discontinuous mode’, embossing
does not start before the foil has reached the target temperature. The foil rests between two parallel heating plates and
foil movement and embossing starts only after the part of the foil resting between the heating plates has reached a thermal
steady state. A new type of embossing master is used which is based on flexible silicon substrates. The embossing pattern
with sub-μm topographic resolution is prepared on silicon wafers by state of the art lithography and dry etching techniques.
The wafers are thinned down to a thickness of 40 μm, which guarantees the mechanical flexibility of the embossing masters.
Up to 20 individual chips with a size of 20 × 20 mm2 were assembled on a roller. Embossing experiments with COC foils showed
a good replication of the silicon master structures in the foil. The maximum depth of the embossed holes was about 70% of
the master height. 相似文献
11.
The present study aims at scaling the formation of slug bubbles in flow-focusing microfluidic devices using a high-speed digital
camera and a micro particle image velocimetry (μ-PIV) system. Experiments were conducted in two different polymethyl methacrylate
square microchannels of respectively 600 × 600 and 400 × 400 μm. N 2 bubbles were generated in glycerol–water mixtures with several concentrations of surfactant sodium dodecyl sulfate. The influence
of gas and liquid flow rates, the viscosity of the liquid phase and the width of the microchannel on the bubble size were
explored. The bubble size was correlated as a function of the width of the microchannel W
c, the ratio of the gas/liquid flow rates Q
g/ Q
l and the liquid Reynolds number. During the pinch-off stage, the variation of the minimum width of the gaseous thread W
m with the remaining time could be scaled as
_boxclose_boxclose ()^ - 0.15 (T - t)^1/3 . W_{\text{m}} \propto ({\frac{{Q_{\text{g}} }}{{Q_{\text{l}} }}})^{ - 0.15} (T - t)^{1/3} . The velocity fields in the liquid phase around the thread, determined by μ-PIV measurements, were obtained around a forming
bubble to reveal the role of the liquid phase. 相似文献
12.
Uniformly sized droplets of soybean oil, MCT (medium-chain fatty acid triglyceride) oil and n-tetradecane with a Sauter mean diameter of d
3,2 = 26–35 μm and a distribution span of 0.21–0.25 have been produced at high throughputs using a 24 × 24 mm silicon microchannel
plate consisting of 23,348 asymmetric channels fabricated by photolithography and deep reactive ion etching. Each channel
consisted of a 10-μm diameter straight-through micro-hole with a length of 70 μm and a 50 × 10 μm micro-slot with a depth
of 30 μm at the outlet of each channel. The maximum dispersed phase flux for monodisperse emulsion generation increased with
decreasing dispersed phase viscosity and ranged from over 120 L m −2 h −1 for soybean oil to 2,700 L m −2 h −1 for n-tetradecane. The droplet generation frequency showed significant channel to channel variations and increased with decreasing
viscosity of the dispersed phase. For n-tetradecane, the maximum mean droplet generation frequency was 250 Hz per single active channel, corresponding to the overall
throughput in the device of 3.2 million droplets per second. The proportion of active channels at high throughputs approached
100% for soybean oil and MCT oil, and 50% for n-tetradecane. The agreement between the experimental and CFD (Computational Fluid Dynamics) results was excellent for soybean
oil and the poorest for n-tetradecane. 相似文献
13.
This study investigates the size limit of a hole produced by the conventional punching process. In the micron size hole punching, there are two main technical obstacles that complicate the miniaturization steps. One is the fabrication of the micro punch tools with high dimensional accuracy and the other is the accurate alignment of the tools within the die clearance of 1∼2 μm. In this study, we tried to mechanically punch a 15 μm size hole. For this, we fabricated and alignedthe punch tools. Micro punch tools made of tungsten carbide were fabricated by micro-electrical discharge machining (micro-EDM). The diameter of punch tip was 15 μm, and that of the die hole, 17 μm. With the developed micro punching system, tools were aligned, and then, 15 μm size holes were made on 13-μm-thick brass and stainless steel foil, respectively. 相似文献
14.
Presented here are details of the development of a novel membrane integrated circuit (IC) probe card structure based on microsystems technology. The device design allows probing of both solder bumps and pads. A self-limiting sensor was integrated to prolong device lifetime. Comparison with and discussion of the use of modelling is made. Possible enhancements to the probing structure are discussed to improve alignment and measurements. Also shown is data using our microsystems probe card to access a simple IC device. Our device has a contact resistance of less than 0.5 Ω for a force of 0.004 N. A method to implement our probing structure for commercial application and the potential developments which can be made to improve its ease of use are then discussed. 相似文献
15.
We have developed a MEMS probe-card technology for wafer-level testing ICs with 1-D line-arrayed or 2-D area-arrayed dense pads layouts. With a novel metal MEMS fabrication technique, an area-arrayed tip matrix is realized with an ultradense tip pitch of $90 muhbox{m} times 196 mu hbox{m}$ for testing 2-D pad layout, and a 50-$muhbox{m}$ minimum pitch is also achieved in line-arrayed probe cards for testing line-on-center or line-on-perimeter wafers. By using the anisotropic etching properties of single-crystalline silicon, novel oblique concave cavities are formed as electroplating moulds for the area-arrayed microprobes. With the micromachined cavity moulds, the probes are firstly electroplated in a silicon wafer and further flip-chip packaged onto a low-temperature cofired ceramic board for signal feeding to an automatic testing equipment. The microprobes can be efficiently released using a silicon-loss technique with a lateral underneath etching. The measured material properties of the electroplated nickel and the Sn–Ag solder bump are promising for IC testing applications. Mechanical tests have verified that the microprobes can withstand a 65-mN probing force, while the tip displacement is 25 $muhbox{m}$, and can reliably work for more than 100 000 touchdowns. The electric test shows that the probe array can provide a low contact resistance of below 1 $Omega$, while the current leakage is only 150 pA at 3.3 V for adjacent probes.$hfill$[2008-0273] 相似文献
16.
Presented here are details of the development of a novel membrane integrated circuit (IC) probe card structure based on microsystems technology. The device design allows probing of both solder bumps and pads. A self-limiting sensor was integrated to prolong device lifetime. Comparison with and discussion of the use of modelling is made. Possible enhancements to the probing structure are discussed to improve alignment and measurements. Also shown is data using our microsystems probe card to access a simple IC device. Our device has a contact resistance of less than 0.5 Ω for a force of 0.004 N. A method to implement our probing structure for commercial application and the potential developments which can be made to improve its ease of use are then discussed. 相似文献
17.
A high-performance MEMS-based gas chromatography (GC) device is proposed comprising a miniature serpentine column with dimensions
of 3.2 m × 200 μm × 250 μm (length × width × depth) and with an integrated Pt micro heater. The column is fabricated on a
Si die measuring 3.5 × 1.8 mm 2 using a wet etching process and is bonded to a Pyrex cover plate incorporating the Pt micro heater via a thermal fusion process.
The experimental results reveal that an applied voltage of 9.7 V is sufficient to maintain a constant temperature of 85°C
for elution purposes. In addition, it is shown that the proposed device successfully detects the concentrations of both pure
and mixed samples of four volatile organic compound gases, namely acetone, toluene, methanol, and benzene. Finally, the theoretical
plate number obtained by the proposed MEMS-based GC device is shown to be 2–3 times higher than that obtained from a conventional
capillary-based GC system under the same injection conditions. 相似文献
18.
In this paper, we developed a hermetic wafer level packaging for MEMS devices. Au–Sn eutectic bonding technology in a relatively
low temperature is used to achieve hermetic sealing, and the vertical through-hole via filled with electroplated copper for
the electrical connection is also used. The MEMS package has the size of 1 mm × 1 mm × 700 μm, and a square loop Au–Sn metallization
of 70 μm in width for hermetic sealing. The robustness of the package is confirmed by several tests such as shear strength
test, reliability tests, and hermeticity test. The reliability issues of Au–Sn bonding technology, and copper through-wafer
interconnection are discussed, and design considerations to improve the reliability are also presented. By applying O 2 plasma ashing and fabrication process optimization, we can achieve the void-free structure within the bonding interface.
The mechanical effects of copper through-vias are also investigated numerically and experimentally. Several factors which
could induce via hole cracking failure are investigated such as thermal expansion mismatch, via etch profile, copper diffusion
phenomenon, and cleaning process. Alternative electroplating process is suggested for preventing Cu diffusion and increasing
the adhesion performance of the electroplating process. 相似文献
19.
Studies have been carried out on a RF MEMS shunt switch to analyze the effect of residual stress on its electromechanical
characteristics. This paper presents the simulated results as well as theoretically calculated results of a shunt switch due
to the presence of residual stress gradient in respect of resonant frequency, pull down voltage and switching characteristics.
The effect of introduction of holes in the beam is also studied. The calculated results, corresponding to the switch (without
holes) at zero residual stress, of resonant frequency, pull-down voltage and switch on and off time are 28.14 kHz, 28.2 V,
16.35 μsec and 8.6 μsec respectively. Modal analysis of the both the structures (with and without holes) are carried out for
different values of residual stress gradients. Modal analysis predicted that higher values of tensile stress gradient are
not favorable for switching action. The pull-down voltages and switch on and off times are simulated at different stress gradients.
With the increase in compressive stress gradient, the pull-down voltage is found to increase, whereas, switch on and off times
is decreased. Corresponding to −20 MPa/μm residual stress gradient, the resonant frequency, pull-down voltage and switch on
and off times are found to be 74.5 kHz, 63.5 V, 7.5 μsec and 3.36 μsec respectively. Introduction holes in the structure modified
these values to 63.77 kHz, 53.1 V, 8.7 μsec, 3.92 μsec respectively. 相似文献
20.
The authors describe a proprietary membrane probe card that addresses the needs of testing VLSI devices at the wafer level. The membrane probe allows the testing of devices with a high pin count at operating speed, while allowing a complete package test at the wafer level. The concepts and structure of the probe are examined, and its performance is demonstrated by time-domain and frequency-domain measurements of the typical electrical characteristics of a VLSI digital probe that accesses 272 pads at a pitch of 110 μm. Applications to a bipolar ECL (emitter-coupled logic) flash A/D (analog-to-digital) converter, a bipolar ECL D/A converter, an application-specific CMOS IC, an NMOS VLSI central processing unit, and area-array solder bumps are presented 相似文献
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